Laboratory of Island Biogeography and Conservation Biology, College of Life Sciences, Nanjing Normal University, Nanjing, China.
J Anim Ecol. 2022 Dec;91(12):2424-2436. doi: 10.1111/1365-2656.13824. Epub 2022 Oct 31.
Nested subset pattern (nestedness) has been raised to explain the distribution of species on islands and habitat fragments for over 60 years. However, previous studies on nestedness focused on species richness and composition and overlooked the role of species traits and phylogeny in generating and explaining nestedness. To address this gap, we sampled amphibians on 37 land-bridge islands in the largest archipelago of China, the Zhoushan Archipelago, to explore nestedness as well as the underlying causal processes through three facets of diversity, that is, taxonomic, functional and phylogenetic diversity. The taxonomic nestedness was measured through organizing the species incidence matrix to achieve a maximum value, while the functional and phylogenetic nestedness were quantified by incorporating the similarity of species in terms of their ecological traits and phylogeny. We also obtained six island characteristics and seven species traits as predictors of nestedness. Amphibian metacommunities were significantly nested in these three facets of diversity. When relating different predictors to nestedness, island area, habitat diversity and species traits were highly correlated with taxonomic nestedness. Moreover, island area and habitat diversity significantly influenced functional and phylogenetic nestedness. Therefore, the results support the selective extinction and habitat nestedness hypotheses. Interestingly, although we did not observe significant influences of island isolation on taxonomic nestedness, functional and phylogenetic diversities were significantly higher than expected when matrices were ordered by increasing distance to mainland. The result suggests that there are more functionally and phylogenetically diverse species on less-isolated islands, reflecting a selective colonization process overlooked by the traditional analysis of taxonomic nestedness. Although the three facets of nestedness and underlying processes were largely congruent, we detected the distance-related functional and phylogenetic nestedness for amphibian assemblages. Therefore, we highlight that a framework that simultaneously considers taxonomic, functional and phylogenetic nestedness can contribute to a complementary understanding of nestedness processes. In addition, it also improves our ability to conserve insular biodiversity from different perspectives.
嵌套子集模式（嵌套性）被提出用来解释 60 多年来物种在岛屿和生境碎片上的分布。然而，以前关于嵌套性的研究集中在物种丰富度和组成上，而忽略了物种特征和系统发育在产生和解释嵌套性方面的作用。为了解决这一差距，我们在中国最大的群岛舟山群岛的 37 个陆桥岛屿上对两栖动物进行了采样，以通过多样性的三个方面，即分类学、功能和系统发育多样性，来探索嵌套性以及潜在的因果过程。分类学嵌套性是通过组织物种发生率矩阵来实现最大值来衡量的，而功能和系统发育嵌套性则通过整合物种在生态特征和系统发育方面的相似性来量化。我们还获得了六个岛屿特征和七个物种特征作为嵌套性的预测因子。两栖动物集合群落在这三个多样性方面表现出显著的嵌套性。当将不同的预测因子与嵌套性相关联时，岛屿面积、生境多样性和物种特征与分类学嵌套性高度相关。此外，岛屿面积和生境多样性显著影响功能和系统发育嵌套性。因此，结果支持选择性灭绝和生境嵌套性假说。有趣的是，尽管我们没有观察到岛屿隔离对分类学嵌套性的显著影响，但当根据与大陆的距离增加来排列矩阵时，功能和系统发育多样性显著高于预期。结果表明，在隔离程度较低的岛屿上，具有更多功能和系统发育多样性的物种更多，反映了传统分类学嵌套性分析忽略的选择性定植过程。尽管嵌套性的三个方面和潜在过程在很大程度上是一致的，但我们检测到了与距离相关的两栖动物集合群落的功能和系统发育嵌套性。因此，我们强调，同时考虑分类学、功能和系统发育嵌套性的框架可以有助于互补理解嵌套性过程。此外，它还提高了我们从不同角度保护岛屿生物多样性的能力。
